A radical plan to deal with Britain’s plutonium waste – the biggest civil deposit in the world – has come a step closer with a legal contract to test the feasibility of building an American nuclear fast reactor on the Sellafield site in Cumbria.

Britain’s own fast-reactor programme was abandoned two decades ago and yesterday it was announced that the fast-reactor site at Dounreay in Scotland will be dismantled by 2025 at a cost of £2.7bn.

However, The Independent can reveal that nuclear officials have signed a feasibility study to investigate the possibility of building an American-designed fast reactor to “burn” the plutonium waste on-site at Sellafield.